Machine cutting tools can be produced from a variety of materials, including but not limited to carbon steel, high-speed steel, cobalt high-speed steel, tungsten carbide, and the like. Cutting tools made from cobalt and/or carbide can withstand higher operating temperatures and can thus be run at higher cutting speeds and feeds than tools made from carbon steel or high-speed steel. Cutting tools containing cobalt and/or carbide, however, may be more time consuming and costly to produce than tools made from carbon steel or high-speed steel due to the increased hardness of the materials.
There exists a variety of known manufacturing methods for producing cutting tools. For example, the process of producing a twist drill from carbon steel may involve rough milling a cylindrically-shaped blank to produce drill flutes in a straight line along the length of the blank. The milled blank can then be heated and twisted to form the flutes into a desired helix. The twist drill can then be semi-finished milled and ground to size. The manufacturing process generally becomes more complex and time consuming when producing cutting tools made from cobalt and/or carbide. For example, manufacturing twist drills from carbide may require more extensive and complex machining operations to produce than tools made from carbon steel of high-speed steel. The time and cost of producing cutting tools from cobalt and/or carbide could be reduced by producing a cutting tool blank that more nearly approximates the finished shape of the cutting tool. Accordingly, there is a need to develop an apparatus and method for manufacturing a cutting tool that more closely approximates the finished shape of the cutting tool being produced.
In accordance with the present invention, a preferred embodiment of a molding apparatus for making a cutting tool includes a cylindrically shaped elastic bag having an internal cavity for receiving a granulated material, such as a mixture of cobalt and carbide. The profile of the interior cavity substantially corresponds to the shape of the cutting tool being produced. The ends of the bag are open to provide access to the interior cavity of the bag. A further aspect of the invention includes a substantially rigid tubular-shaped pressure sleeve that encloses an outer circumference of the elastic bag. Yet another aspect of the invention includes a pair of end caps that operate to seal the open ends of the elastic bag and are engageable with the ends of the pressure sleeve. The granulated material can be formed into a solid coherent structure by placing the assembled mold containing the granulated material into a hydrostatic press for applying a substantially uniform compressive load to the outer periphery of the elastic bag. After forming, the cutting tool blank can be removed from the mold and may be subjected to further processing.